Johann Karl Friedrich Zöllner (8 November 1834 – 25 April 1882) adalah seorang astrofisikawan Jerman yang mengkaji ilusi optik. Ia juga merupakan seorang investigator psikikal.

• Transcendental Physics (English edition, translated by Charles Massey, 1880)

• Hereward Carrington. (1907). The Physical Phenomena of Spiritualism. Herbert B. Turner & Co.
• Joseph Jastrow. (1901). Fact and Fable in Psychology. Macmillan and Company.
• Eleanor Mildred Sidgwick. (1886–87) Results of a Personal Investigation into the 'Physical Phenomena' of Spiritualism. With Some Critical Remarks on the Evidence for the Genuineness of Such Phenomena. Proceedings of the Society for Psychical Research 4: 45-74.
• Ulrici, Hermann. (1879). Der sogenannte Spititismus eine wissenschaftliche Frage. Zeitschrift für Philosophie und philosophische Kritik 74: 239-271.
• Wundt, Wilhelm. (1879). Spiritualism as a Scientific Question: An Open Letter to Professor Hermann Ulrici, of Halle. Popular Science 15: 577-593.

• Works at Open Library